Ariel Simulation
This is a simulation of what one would expect to find on a terraformed Ariel, using formulas from Math And Terraforming. Please note that not even the supercomputers at NASA can provide us with a perfect simulation. The information showed here is only an approximation. Basic data *Distance from Sun: 2875.04 million km *Distance from Uranus: 0.191 million km *Diameter: 1158 km *Solar Constant: 0.00535 *Mass: 0.000226 Earths *Mean density: 1.592 kg/l *Uranus's period: 84.021 Earth years *Day length: 2.520 Earth days *Rotation axial tilt: 98 degrees (82 degrees, retrograde) Atmosphere See Atmosphere Parameters Given the very low gravity, it will be difficult for Ariel to hold an atmosphere. During this simulation, we will use an atmosphere with the same pressure at sea level as Earth's and a similar composition. *Atmosphere stability for oxygen molecules: **Earth's gravity (15 degrees C): 4.116 **Ariel's gravity (15 degrees C): 82.53 **Ariel's gravity (-175 degrees C): 28.11 *Atmosphere stability for water molecules: **Earth's gravity (15 degrees C): 7.320 **Ariel's gravity (15 degrees C): 146.7 **Ariel's gravity (-175 degrees C): 49.98 *Atmosphere stability for hydrogen molecules: **Earth's gravity (15 degrees C): 65.88 **Ariel's gravity (15 degrees C): 1320 **Ariel's gravity (-175 degrees C): 908.0 notes: A value below 10 means stability for over a million years, a value between 10 and 100 means stability between 0.1 and 10 millions of years, while a value higher then 100 means stability for less then 10 thousand years. This calculation does not include solar wind erosion. Conclusion: The atmosphere of Ariel will be divided in two distinct layers, separated by a greenhouse gas buffer. In the upper layer, where temperature will be low, oxygen and nitrogen can be held for thousands of years. However, water vapors, if they make their way that far, will be lost into space. In the lower layer, even oxygen is nearly unstable. Water vapors will fast rise to the upper layer. Hydrogen, resulting from interaction between water molecules and ionizing radiation, will escape into space very fast. Ariel lies deep into Uranus's magnetosphere, so it will be protected from solar wind erosion, which anyway is not strong at this distance. The atmosphere will look like this: Ground average temperature: 15 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 1.24 *Atmosphere breathable height: 473 km *Atmosphere total height: 1407 km Ground average temperature: -175 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 0.66 *Atmosphere breathable height: 280 km *Atmosphere total height: 833 km Combined values *Atmosphere total mass (Earth = 1): 0.91 *Atmosphere breathable height: 380 km *Atmosphere total height: 1100 km. As one can see, Ariel will have a very fluffy atmosphere, as high as its diameter. However, at that height, gravity is smaller (1/4), making the atmosphere to extend much further. Also, at that distance, speed of gas molecules get close to the escape velocity. Because of this, the moon will lose its upper atmosphere fast. However, the loss will not be so high and air pressure will not decrease significantly during a human lifetime. The moon could be habitable for a thousand years. Temperature Main article: Temperature. The first problem with Ariel is that we need to gain the correct surface temperature. The Solar Constant is small (0.00535), compared to Earth (1.98). We will need Greenhouse Gases. The Greenhouse Calculator shows us that Titan will need 2.68 kg/sqm of sulfur hexafluoride. Climate Simulation Main article: Climate. On Earth, the average temperature is +15 degrees C. Technicians will try, with the help of greenhouse gases, to keep this temperature. Ariel has a smaller diameter then Earth (0.091), so air currents can mix temperatures faster. The atmosphere will be high enough to pass over all Geographic barriers. Average temperatures for each latitude: At equinox: *poles: 14.7 C *75 deg: 14.9 C *60 deg: 15.0 C *45 deg: 15.0 C *30 deg: 15.1 C *15 deg: 15.1 C *equator: 15.2 C At winter solstice: *poles: 14.4 C *75 deg: 14.5 C *60 deg: 14.6 C *45 deg: 14.7 C *30 deg: 14.7 C *15 deg: 14.8 C *equator: 14.8 C At summer solstice: *poles: 15.1 C *75 deg: 15.1 C *60 deg: 15.1 C *45 deg: 15.0 C *30 deg: 15.0 C *15 deg: 14.9 C *equator: 14.8 C Day - night cycle variation: Ariel has an average day length (2.520 Earth days), but is well protected by its greenhouse layer. So, temperature variations between day and night will not be significant. *Daily temperature variation: 0.15 degrees C *Equator day-night variations: **Equinox: 15.1 to 15.3 degrees C **Solstice: 15.0 to 15.2 degrees C *Day - night variations for 45 deg latitude: **Equinox: 14.9 to 15.1 degrees C **Winter solstice: polar night, no variation **Summer solstice: polar day, no variation Seasons: Uranus has the most tilted axis in the Solar System, shared by all its inner moons. Because of the extremely long uranian year, one hemisphere will be covered in darkness for a long time, while the other hemisphere will experience a long polar day. However, because of the strong greenhouse effect needed, the moon will not experience temperature changes. At the poles, temperature will change between 14.4 and 15.1 (a variation of only 0.6 degrees C). Altitude variations: Given the fluffy atmosphere that will be created, pressure will not decrease significantly. A mountain 45 km high on Ariel will experience a temperature change like a mountain that is 1 km high on Earth. So, temperature variations caused by altitude should be ignored. Conclusion. Ariel will experience a climate pattern known as monoclime, with very small temperature variations. In such conditions, winds will be very slow, but highly predictable. They will exchange temperatures between hemispheres. With little temperature variations, the atmosphere will get saturated with moisture. It will be a very wet climate, with many hazes and clouds. Still, because temperature will not drop significantly, it will not rain much. Still, Ariel has an advantage, that can bring some climate changes from time to time. Above the greenhouse gas layer, during long polar nights, the atmosphere will condense and will start to snow. When this will happen, it will bring a significant decrease of temperature, that will stimulate winds to form. This phenomena can decrease temperature significantly, forcing the clouds to rain. Then, cooled air will move to the illuminated hemisphere, where it will heat-up, absorbing moisture. This phenomena can produce a few days of clear blue sky. After this, the moon will gradually heat-up back to its stability temperature value. Geography See also: Geography, Geographic Pattern - Tectonic and Geographic Pattern - Craters. It appears that Ariel contains about half water ice and half other materials. There is a high chance that the moon is differentiated into an icy crust and a rocky core. At least in past, it had a subsurface ocean, which currently might be frozen. Terraformers have 4 major ways to transform an icy Outer Planet: #Increase the heat, melt the ice and transform it into an Oceanic Planet, then leave it as it is. #If possible, build Artificial Continents after melting all the ice. #Use Ground Insulation, to save the icy crust, then cover it with solid rock. # Heat the moon, until solid particles from the molten ice will form a natural insulation above the ice crust (see Iapetus Simulation). The first option, without an added source of heat, will take us a lot of time. at Uranus's distance, solar radiation is weak. The ice will melt with an average speed of 3.9 mm melt daily and 1.38 meters melt in an Earth year (see Adjusting Temperature for details). It will take us 72500 years to melt the ice down to 100 km. Still, if we manage to heat the moon somehow, then the ice will completely melt and we will have an oceanic world. Then, it is possible to build artificial continents, an option that is possible here, because the moon is not mostly made of ice. It contains also other materials that can be used. The third option, that of using ground insulation, might be possible using materials that already exist on the moon. However, it is costly, even if far less costly then the heating of all ice. The fourth option is also possible. If we use a source of heat, to melt the ice down to 200 m, then debris kept in the ice will form a layer of ground that might be 20 to 50 m thick. This insulation layer will reduce ice melting speed significantly. And because the icy crust is very cold (and will remain cold for a long time), it is expected that, at least for a few thousand years, water will freeze at the bottom of the insulation layer. The major problem for all variants is that Ariel has its atmosphere pushed to the limit. A slight increase in heat on the surface might cause the atmosphere to expand beyond a critical point and be lost in space. 1. Oceanic planet: In this scenario, Ariel will have a very deep, global ocean, with no island. Manmade floating islands can exist, still. The ocean, because of the lack of winds, will have only very small waves. Water will help mix temperatures. 2. Artificial continents: In this scenario, there will be large floating islands. Because the ocean is expected to lack powerful currents, continents will remain to their positions for a long time. To save budget, it is expected that continental crust will not be thick. So, high mountains will not exist. 3. Ground insulation: In this scenario, the moon will be covered with a global protective layer, that will insulate the ice for millennia. Many Geographic features will be altered (mountains excavated, craters filled), so the resulting terrains will be different. Probably, oceans will cover 50% of the surface. 4. Natural ground insulation: This option, the cheapest of all, will create erosion valleys on the surface and depressions filled with sediments. Water, being heavier then ice, will sink through holes and pores into the moon, freezing at a certain depth. Almost all Geographic features will be preserved. Ground will be covered with black soil. There will be no or almost no lakes. 5. Alternative Ocean Simulation: See also: Ocean Insulation. There is another option, which was proposed in a Soviet sci-fi novel. It is interesting that, at the time the novel was written, no spaceship visited any giant planet. Still, the author realized that out there might be icy moons and icy planets. The idea is to cover the surface of an icy moon with a transparent material, that will provide a very powerful insulation. Light will pass through, but heat will remain trapped beneath. The insulation layer will compress the ice (and later the ocean) with its mass, like an atmosphere, preventing water from escaping into space. What materials can we use for that? It should be somehow elastic, to resist the tensions beneath. Maybe, sulfur hexafluoride, dissolved in some organic compound, will do the job. Given the little gravity (0.027 of Earth's), we will need a layer of 40 meters, to have above the ocean a pressure of 0.1 bar. Still, some volatiles from the insulation will sublimate and form a tenuous atmosphere around Ariel. With this technology, we can protect the ocean without creating a massive atmosphere layer. And to heat the ocean, we can use large nuclear reactors, buried deep inside the ice crust. However, we will not have a breathable atmosphere. With this solution, Ariel will be spherical, without any Geographic features on the surface. It will be an endless ocean, covered by an insulation layer. Conclusion: The large atmosphere will be unsustainable for a long time. Heat from terraforming activities (like melting the ice) can make the atmosphere escape into space. The use of an ocean insulation layer should work for Ariel better then other solutions. However, this will erase any Geographic features the moon once had. The Sky As any Outer Planet, Titania will have a lot of moisture in its atmosphere. The blue sky will be visible on rare occasions, that will probably be holidays on the surface. Still, from orbit, some celestial bodies will be visible. The Sun will appear 0.48 units wide (like an object 0.48 mm wide will appear if you look from a distance of 1 m, see Angular Size for details). Uranus and other satellites visible as disks will be: *Uranus - 266 units *Miranda - 1.48 to 7.21 units *Umbriel - 2.80 to 33.40 units *Titania - 2.15 to 6.43 units *Oberon - 1.97 to 3.88 units Some planets will also be visible, with a Magnitude as follows: *Mercury: 6.2 to 6.3 *Venus: 3.3 to 3.5 *Earth: 4.5 to 4.8 *Mars: 5.9 to >6 *Jupiter: 2.3 to 3.5 *Saturn: 2.9 to 5.3 Please note that values are calculating assuming that a planet is visible as a full moon and not as a crescent. Inner planets will only be seen as crescents, so their visible magnitude will always be with about one unit higher. So, Mercury and Mars will actually not be visible. On the other hand, a planet that is too close to a source of light like the Sun will actually not be visible. Because of this, only Jupiter and Saturn could be seen with the naked eye. Human Colonies *Population limit: 90 000 *Land population feeding capacity: 0.9 people fed from one square km *Largest city supported by environment: 360 people Assuming it will have similar types of terrain Earth will have, Titania can support a Population Limit of 90 000 people. Ariel will have its atmosphere at a critical equilibrium state. Too much heat and it will be lost. The small population limit, combined with the huge terraforming costs and the short lived atmosphere, make terraforming not feasible. However, if we use an ocean insulation, population limit will increase significantly, because heat from human activities can be radiated above the insulation. Also, if we want to cool the moon, by just opening the insulation, this will happen fast. Without a breathable atmosphere (assuming ocean insulation will be made), colonies will have to extract their oxygen from water. Industry If we will use ocean insulation, then Ariel will become a unique oceanic world. A lot of industrial activities can be developed. The moon might contain a lot of minerals dissolved in its oceans. Also, it will be possible to mine directly from the rocky core, now only covered with ice. The moon might contain organics (tholins) and other carbon compounds, as well as other lighter minerals, very important in terraforming (like sulfur, phosphorus, sodium and magnesium). Concentration of metals and mainly of heavy elements is not expected to be high. The presence of these materials can stimulate the development of some industrial branches. Agriculture With very little illumination, it will be very hard for plants (see Plants on new worlds for details). However, if we use the ocean insulation method, then Ariel will not have its sky covered with clouds and hazes. There will be more light and this will benefit ocean life. Humans will be able to find food in the ocean. Transportation If the moon will have an atmosphere, then air transport will become the best way to move things around. However, if we will use ocean insulation, then the best way to move around will be by submarine. Since Ariel is tidal locked, there is no place for geosynchronous satellites. Still, there are some safe orbits around the moon for satellites that will provide telecommunications. The large atmosphere will pose major challenges for radio waves. There will be constructed at least one base on the surface, for space travel. Large interplanetary ships, carrying passengers and cargo to and from Saturn, will dock at Perdita. Then, smaller ships will ferry between the little moon Helene and Ariel. Tourism By using the ocean insulation method, Ariel will become a unique world. This will certainly attract tourists. Wild Life Assuming the ocean insulation method will be used, then oceans will offer the only place for life. Birds and mammals will not exist, because there will be no air to breath for them. Still, many species of algae and fish will adapt to this environment. Category:Simulation Category:Math